The present invention relates to a receptacle or socket for a round connector or plug having the same contact pattern. The periphery of the shell of the plug, in the insertion region thereof, is provided with a guide key and several (preferably four) coding keys; the keys can be disposed at various angular positions relative to one another.
The aforementioned features for preventing a false coupling, such as keys and keyways in different angular positions relative to one another, are used in order, with a given shell size and the same contact pattern of the round plug connection, to prevent polarization and hence failures or malfunctions.
To fulfill this requirement while the position of the contact insert or insulator in the socket housing remains the same, it is known to undertake either
(a) a coding by five different angular positions of the main keyway while the position of the coding notches in the housing remains the same (see, for example, the Verteidigungsgeratenorm document VG 96912), or PA1 (b) a coding with six different angular positions of four coding notches while the position of the main keyway of the housing remains the same (see, for example, the Verteidigungsgeratenorm document VG 95329).
To test cables equipped with plugs of the types described in the aforementioned VG documents via cable testing devices, it is necessary to provide for each plug-coding position a socket having the pertaining coding and the electrical connections to the testing device.
For example, with round plug connections of the VG 96912 type, for nine different shell sizes and 25 contact patterns, selectively provided with sleeves or pin contacts, a total of 246 different plug sizes can be taken as possible and being involved therewith. Thus, 246 matching sockets are also necessary for cable testing.
With round plug connections of the VG 95329 type, for six different shell sizes and 12 contact patterns, selectively provided with sleeves or pin contacts, a total of 144 different plugs can be taken as possible and being involved therewith. Thus, 144 matching sockets are also required for cable testing.
However, to test cables with such plugs, the prevention of a false coupling achieved by the coding measures is not necessary, since it is necessary only to carry out electrical tests, namely contact and insulation tests, that are independent of the coding positions, whereas a visual inspection is sufficient to test the coding positions, i.e. the position of the guide and coding keys on the plugs.
It is an object of the present invention to reduce the number of sockets for carrying out cable tests (contact and insulation tests) where the cables are provided with round plugs, for example of the known prior art identified as norm series VG 96912 or VG 95329 type dated September 1982 and November 1972, respectively.